There are two components that go into a completed passing play; the distance the ball travels in the air, and the yards the receiver gains after the catch. The Air Yards tell a story for both the QB and his receiver. A QB with a high Air Yardage amount means he likes to take shots downfield. For a WR that’s what we want, more yards = more fantasy points. Therefor a low amount means he is a low risk passer, throwing underneath a lot. Meanwhile for a receiver, the higher the Air Yardage means they are more of a downfield Receiver, and the lower means they are more of a slot / short yardage receiver. Yards After the Catch on the other hand measures how effective the receiver is after catching the ball. Both are very important when evaluating a receiver, but for fantasy purposes which is more important.
*Sample is for WRs with more than 800 total yards in 2018
Below are 2018’s leaders in total Air Yards. A lot of this makes sense as Evans was playing with gunslingers Fitzmagic and Winston. Meanwhile McCaffrey’s AY is obviously low since he’s a RB. Some interesting names are pretty high on the list like Zack Ertz, Adam Thielen etc.
Now doing the same for YAC, most of the totals are pretty linear but then we have two seismic margins in CMC and Kitle. CMC makes sense, he gets the ball close to the line of scrimmage and then has space to run. Kittle is an interesting one. He certainly made the most after catching passes from Beathard and Mullens.
Combining the two charts from above we have each receivers total yardage amount in 2018 with their Air Yards in green and YAC in blue. This gives a good idea for how much AY matters for WR performance. For most of the WRs the AY total represents more than 50% of their yards. However I am fascinated by Kittle’s bar, so many of his yards came from his YAC. In my opinion AY matters more than YAC as it is more of a safe assumption for WR performance. A WR’s performance depends more on where their QB gives them the ball than what they are able to do after it. But let’s back this up with statistics.
As always, target share is obviously the most important factor in evaluating a receiver, but what’s next. Below is a chart measuring the relationship between Air Yards and fantasy points. We have an R Squared of 0.63 which means that Air Yards “explains” 63% of the variation in fantasy points. This is a very good result considering the context of this analysis. So now we know how much AY matters statistically, what about YAC.
I removed CMC since he is technically a RB and should have different results. About a third of the R Squared amount and a lot of that is due to that marker alllll the way on the right and guess who it is, George Kittle. When I removed Kittle the R-Squared jumped to about 0.38. Both results are very good and matter for fantasy purposes. But clearly Air Yards are more important than YAC.
When deciding what WRs to draft, the first thing to take into account is target share. We want WRs who have a high share of their QBs pass attempts. After that it should be Air Yards, we also want WRs who get downfield and have deeper looks from their QBs. YAC is a nice thing to factor in as well, but it has a higher variance than AY. Because of this I would hypothesize that someone like Kittle will either stay the same or regress in 2019. I know Jimmy will probably get his Air Yards up so thats why I say he could stay the same fantasy wise (more AY less YAC), but his YAC just seems to be so unsustainable.